Browse on keywords: fertility WA green manure
Search results on 10/17/18
3875. Leggett, G.E. and W.L. Nelson. 1960. Wheat production as influenced by cropping sequence and nitrogen fertilization.. WA Agr. Expt. Sta. Bull. #608.
The average wheat yields resulting from annual cropping with optimum nitrogen fertilization were 13 bu/ac at Ritzville, 23 and Harrington and 29 at Dusty. The yields at Ritzville were too low for this practice to compete economically with the summer-fallow system. The average yields were high enough at Harrington and Dusty for this cropping system to be seriously considered. At Dusty annual cropping resulted in a yearly average yield of 6 bu/ac more than was obtained on fallowed ground. The yield of wheat following Austrian winter peas as a green manure crop at Dusty was greater than that obtained after alfalfa or sweetclover. Soil analysis revealed that nitrogen fertilization resulted in a carryover of nitrate-nitrogen for subsequent crops. This was especially notable under annual cropping and with high rates of application on summer-fallow. The protein content of the wheat was increased markedly by nitrogen fertilization. T: Nitrate-nitrogen in the soil before fertilization and the available soil moisture used by wheat as influenced by nitrogen fertilization cropping practice, Dusty. Yields of barley and wheat as influenced by alfalfa, sweetclover, and Austrian winter peas as green manure crops.
5065. Patten, A.G.. 1982. Comparison of nitrogen and phosphorous flows on an organic and conventional farm.. M.S. Thesis, Dept. of Agronomy and Soils, WSU, Pullman, WA.
Two adjacent farms, one organically managed and the other conventionally managed, located in the Palouse region of eastern WA, were studied for 2 years. Soil organic matter, total N, extractable P, and extractable K tended to be higher in the top 30 cm of soil from the organic farm. Mineral nitrogen in the top 30 cm of soil from the conventional farm was higher than or equal to that of the organic farm. Average long-term changes calculated in soil N and P pools resulted in substantial deficits of 44 and 14 kg/ha/yr, respectively, for the organic farm and 23 and 5 kg/ha/yr for the conventional farm. However, nutrients deficits were not reflected in lower soil N and P levels in the plot area tested on the organic farm as compared to the plot area on the conventional farm.
7761. Zentner, R.P., E.D. Spratt, H. Reisdorf and C.A. Campbell. 1987. Effect of crop rotation and N and P fertilizer on yields of spring wheat grown on a black chernozemic clay.. Can. J. Plant Sci., 67:965-982.
Including grass-legume forage, or legume green manure crops in the rotation increased yields of wheat grown on the unfertilized partial fallow by 15-24% and on unfertilized stubble by 33-71%; the yields were similar and sometimes higher than those obtained on fallow in the well-fertilized monoculture wheat rotations. Yields of fallow- and stubble-wheat were generally maintained over time with the application of recommended rates of N and P fertilizers, or by inclusion of legume-forage crops in the rotation, but yields of unfertilized stubble-wheat declined with time possibly reflecting declining soil fertility.
8735. Haimanot, K.. 1977. Long-term effects of crop and soil management practices on crop yield and soil chemical composition.. M.S. Thesis, Dept. of Agronomy and Soils, Washington, ST. Univ., Pullman, WA 99164-6420.
The study site was located near Dusty, WA in the intermediate rainfall zone. Cropping system treatments were run from 1952 to 1970. Thirteen different cropping systems with three N fertilizer levels were used, including continuous cropping, green manures, and fallow systems. Wheat yields in rotation using 30 lb N/ac were higher than yields in an alfalfa rotation. Wheat yields were higher after Austrian winter pea green manure than after alfalfa or sweetclover. Per acre per year crop yields were highest for fertilized, continuous cropping. Soil pH increased with sweetclover GM and decreased with N fertilizer added. Significant increases in soil organic matter occurred in rotations with alfalfa (+0.08%), on winter wheat - fallow (+0.30%), and with winter wheat - spring wheat - fallow with N (+0.26%).